Roller bearing arrangement for railroad car truck

ABSTRACT

The invention relates to a railroad car truck in which the side frames are carried inboard of the wheels on supports that are stationary relative to the side frames. The side frames are provided with spring seats that are substantially aligned with the planes of the wheels on either side of the truck and support through spring groups a bolster of special design that supports the weight of the car body at two points on either side of the bolster, which points are aligned with the respective spring groups. The truck bolster is pivoted to the car body bolster by the usual kingpin, but the coupling arrangement involved is such that none of the body weight is supported at the customary center plate area of the bolster, which area is eliminated in the present truck. The truck bolster at its midportion includes a socket structure into which a projection of the body bolster fits for applying longitudinally and laterally acting forces to the bolster from which they are transferred to the side frames through suitable engaging surfaces. In one form of the invention, the side frames are mounted on tubular housings for the axles, which housings are journalled relative to the wheels through special roller bearing or friction bearing arrangements that are herein disclosed. In another form of the invention, the side frames are mounted directly on the axles, which are stationary relative thereto, and which have the truck wheels journalled on the respective ends through a special friction type bearing arrangement, with the result that the truck wheels rotate independently of each other.

United States Patent Oelkers, deceased et al.

[54] ROLLER BEARING ARRANGEMENT FOR RAILROAD CAR TRUCK Filed: May 22,1970 Appl. N0.: 38,645

Related U.S. Application Data Division of Ser. No. 688,037, Dec. 5,1967, Pat. No. 3,570,409.

U.S. Cl ..308/2l1 Int. Cl. ..F 16c 19/14 Field of Search...308/207.1,210, 209, 208, 214,

[56] References Cited UNITED STATES PATENTS 691,922 l/l902 Whitely etal. ..308/207 Primary ExaminerMartin P. Schwadron AssistantExaminerFrank Susko Attorne1vMann, Brown, McWilliams & Bradway [5 7]ABSTRACT The invention relates to a railroad car truck in which the sideframes are carried inboard of the wheels on supports that are stationaryrelative to the side frames. The side frames are provided with springseats that are substantially aligned with the planes of the wheels oneither side of the truck and support through spring groups a bolster ofspecial design that supports the weight of the car body at two points oneither side of the bolster, which points are aligned with the respectivespring groups. The truck bolster is pivoted to the car body bolster bythe usual kingpin, but the coupling arrangement involved is such thatnone of the body weight is supported at the customary center plate areaof the bolster, which area is eliminated in the present truck. The truckbolster at its midportion includes a socket structure into which aprojection of the body bolster fits for applying longitudinally andlaterally acting forces to the bolster from which they are transferredto the side frames through suitable engaging surfaces.

In one form of the invention, the side frames are mounted on tubularhousings for the axles, which housings are joumalled relative to thewheels through special roller bearing or friction bearing arrangementsthat are herein disclosed.

In another form of the invention, the side frames are mounted directlyon the axles, which are stationary relative thereto, and which have thetruck wheels journalled on the respective ends through a specialfriction type bearing arrangement, with the result that the truck wheelsrotate independently of each other.

3 Claims, 19 Drawing Figures PATENTEDBBT 3 I97? SHEET 2 BF 5PATENTEDucra 1912 3.695.739

sum u or s llllll PATENTEDucI 3 m2 sum 5 or 5 IN VE N TOR ALF D H.OELKERS 286 296 ATT'YS.

1 I 1 1/ w g I I g ROLLER BEARING ARRANGEMENT FOR RAILROAD CAR TRUCKThis application is a division of my copending application Ser. No.688,037, filed Dec. 5, 1967 now U.S. Pat. No. 3,570,409.

My invention relates to a railroad car truck, and more particularly, toa car truck of the inboard type in which the vertical load supported bythe truck is in substantial alignment with the track rails.

Conventional railway car trucks customarily have the truck side framesresting on the truck axles outboard of the wheels, and carry the weightof the car body on the truck bolster at its center plate area, where thetruck is pivoted to the car body and the truck and body bolsterso-called center plates engage.

My studies and analysis of railroad car truck operation have revealedthat such an arrangement unnecessarily introduces excessive bendingmoments and resulting stresses on the truck bolster, axles, and wheels,due to the fact that the vertical loads carried by the truck are appliedat the center of the bolster and then must be transferred outboard ofthe truck wheel onto the side frames that then transmit the loads to thecustomary axle journals from which the loads are transmitted to thewheels.

Furthermore, it has been customary to design a truck bolster so that itcan support the entire portion of the car weight the truck is to carryat either side hearing, as well as at the center plate.

The result is that the truck bolsters and axles are made longer andstronger than they need be if the vertical loads were transmitted moredirectly to the rails.

This problem has become particularly acute in view of the current trendtoward higher capacity cars in the lOO-ton and above range, where theloads involved make strength requirements insofar as the truck isconcerned especially critical. Furthermore, freight car trucks encountera wide range of loadings, speeds, and track conditions in interchangeservice, and thus must be designed to handle these variations whileproviding years of trouble-free service.

The principal object of this invention is to provide a railway car truckarrangement in which the vertical loads imposed on a truck aretransmitted substantially directly through the truck to the railswhereby undesirable moments and resulting stresses are eliminated orminimized.

A further principal object of the invention is to provide a four-wheeltruck in which the weight of the car body is supported as close as ispractical to vertical alignment with the rails.

Further objects of the invention are to provide an inboard type railroadcar truck in which the wide frames are carried inboard of the wheels onsupports that are stationary relative to the side frames, to providefriction and roller type journalling arrangements for journalling thewheels relative to the side frames, and to provide a railway car truckarrangement that is of relatively light weight construction and iseconomical of manufacture, that is convenient to install and service,and that is adaptable for use under a wide variety of service conditionson a long term trouble-free basis.

Still other objects, uses, and advantages will be obvious or becomeapparent from a consideration of the following detailed description andthe application drawings.

In the drawings:

FIG. 1 is a plan view of a railway car truck showing one embodiment ofthe invention;

FIG. 2 is a side elevational view of the truck shown in FIG. 1, with oneof the wheels omitted to facilitate illustration;

FIG. 3 is an end view of the truck shown in FIGS. 1 and 2, taken fromthe right hand side of FIG. I, and illustrating in the broken lineposition, at the right hand side of FIG. 3, the location of a standardrailroad car truck axle journal, for comparative purposes, and which isomitted in accordance with this invention;

FIG. 4 is a top plan view of the bolster employed in the truck of FIGS.1-3;

FIGS. 5 and 6 are fragmental cross-sectional views substantially alonglines 55 and 66 of FIG. 4, illustrating the side bearing arrangementemployed in connection with the truck of FIGS. [-3;

FIG. 7 is a side elevational view of the bolster shown in FIG. 4, partsbeing shown in section;

FIG. 8 is an end view of the bolster shown in FIG. 7, parts being shownin section;

FIG. 8A is a fragmental cross-sectional view along line 8A-8A of FIG. 4;

FIG. 9 is a cross-sectional view substantially alon line 99 ofFIG. l;

FIG. 10 is a large fragmental elevational view of one of the truckwheels associated side frame and bearing arrangement, shown partially insection substantially along line l0l0 of FIG. 1;

FIG. 10A is an enlarged sectional view of the roller bearing arrangementshown in FIG. 10;

FIG. 11 is a plan view of one of the side frames shown in the truck ofFIGS. 1-3 together with a portion of the cross member that connects sameto the other side frame of the truck;

FIG. 12 is a side elevational view of the side frame shown in FIG. 1 1;

FIG. 13 is an end view of the side frame shown in FIG. 12, taken fromthe right hand side of that figure;

FIG. 14 is a cross-sectional view through the side frame takensubstantially along line 1414 of FIG. 1 1;

FIG. 15 is a fragmental view similar to the view of FIG. 10 butillustrating a modified embodiment of the invention;

FIG. 16 is a view similar to that of FIGS. 10 and 15 but illustrating afurther modified form of the invention; and

FIG. 17 is a diagrammatic cross-sectional view substantially along line17-l7 of FIG. 16.

However, it is to be understood that the specific drawing illustrationsprovided are supplied primarily to comply with requirements of thepatent code, and that the invention may have other embodiments that areintended to be covered by the accompanying claims.

GENERAL DESCRIPTION Reference numeral 10 of FIGS. 1-3 generallyindicates one embodiment of my invention in which the truck 10 comprisesspaced side frames 12 supported on tubular housings 14 of the respectiveaxles 16 see FIG. 9) on which are mounted wheels 18.

The individual housings 14 of the respective axles 16 are stationarywith respect to the side frames 12 and wheels 18 are joumalled withrespect to the respective housing ends 20 by bearing units 22, which inthe embodiment of FIGS. 1-14 takes the form of a special tapered rollerbearing unit.

The side frames 12 are each formed with a spring seat structure orplatform 24 on which a spring group indicated at 26 is mounted tosupport a bolster 28 that at either end thereof is formed with a similarspring seat structure or platform 30 against which the respective springgroupings 26 engage.

The truck is pivotally connected to the car body by a suitable kingpin32 (see FIGS. 3 and 9), with the kingpin being applied, broadlyspeaking, between the truck side frames and bolster and the car bodybolster generally indicated at 34 in FIG. 9.

In accordance with the present invention, the usual center plateconstruction of the truck bolster is omitted and the truck bolster 28 isformed with a centrally located annular guide structure 36 that looselyreceives a cylindrical extension 38 that, for existing cars, is affixedto the car body bolster center plate structure 40, as at 41 as bywelding), and for new cars will be an integral part of the body bolsteror car body where the body bolster is eliminated.

Instead of the weight of the car body being supported at the truckbolster center plate as in present standard AAR structure, the weight ofthe car body in accordance with my invention rests on the truck bolsterthrough a pair of spaced constant contact side bearings 42 that arepositioned in alignment with the respective spring groupings 26 see FIG.9).

In the embodiment 10A of FIG. 15, the axle housings 14 are omitted andthe side frames are applied directly to the axles which are stationarywith respect to the side frames. In this embodiment, the railway truckwheels 18A are journalled on the respective ends 44 of the axles througha special friction bearing arrangement generally indicated at 22A, withthe individual wheels being held in place by nuts 46 and 48 cooperatingwith lock washer 50.

In the embodiment 10B of FIGS. 16 and 17, the tubular axle housings 14are retained and the axle wheels 18B are journalled with respect theretoby a special friction type bearing unit 22B.

It will therefore be seen that the railway car truck of this inventiondistinguishes from prior art arrangements in a number of importantparticulars.

For instance, the side frames of the truck are inboard of the truckwheels see FIG. 3), and the loads transmitted by the car body throughthe truck to the rails are transmitted through the truck in nearvertical alignment with the truck rails (see FIGS. 3, 9 and 10). Thereis no car body load support function performed by the truck at thepivotal connection provided by kingpin 32.

Furthermore, the side frames as such are supported by supports that arestationary relative thereto; in the forms of FIGS. l-l4 and 16 and 17,the side frames are supported by the housings 14 of axles 16, while inthe form of FIG. 15, the side frames are supported directly bynon-rotating axles.

It will thus be noted that in accordance with this invention, thebending moments and resulting stresses imposed on the truck componentsby supporting the car body weight at the truck center plate area, andsupporting the side frames on axle journals that are disposed outboardof the truck wheels (such as is indicated at 60 in FIG. 3) areeliminated, thereby avoiding overstressing of the bolster, axles, andwheels when heavy loads are imposed on the truck. I-leretofore, it hasbeen general practice to design the trucks so that the entire weight ofthe car body can be supported at either side bearing or at the carcenter plate, and if AAR standard outboard side frame mountingarrangements are employed, difficulties will be encountered due tooverstressing especially when the modern high capacity cars travel atfreight train speeds along lines that are built for high speed passengertrains, when banked curves and the like impose high off center stresseson the truck.

It will also be noted that in all forms of the invention, the railwaycar wheel disc (as distinguished from its hub) employs a relativelylarge bore as compared to standard AAR practice. I prefer that the borebe on the order of 15 inches and this is the result of my analysis ofthe diaphragm action that commonly occurs to railway car wheels underheavy loads. I have determined that having a wheel plate area 62 (seeFIG. 10) of less radial distance will materially reduce the diaphragmeffect if not eliminate same due to the significantly reduced leverageinvolved that acts on the wheel as it resists lateral forces due toweights imposed on the truck as a result of the engagement of the wheelflange 64 with the inside of the rail. The large bore of the wheel alsopermits a practical application of the wheel to its hub by a shoppractice of shrinking a heated wheel onto a cold hub, instead of using alarge press to force the wheel onto the axle as is now common practice.

Other significant advantages will be referred to and explained in detailas the description proceeds.

SPECIFIC DESCRIPTION The details of the side frames 12 are illustratedin FIGS. 11-14 in which it will be seen that each side frame comprises acasting forming a side frame member defining spring seat 24 that isshaped as indicated at 72 to accommodate a number of compression springs74. As indicated in FIGS. 1 3 and 11, the side frame member 70preferably is enlarged as at 76 so that the outer row of springs 74 willbe in substantial alignment with the truck wheels 18 when the sideframes and bolster are in operative relation as part of the truck.

In the particular design here shown all of the eight springs 72 per sideframe are each the AAR class D4 double coils selected for the trucks tocarry a IOO-ton capacity car. For cars of different capacity, springs ofother capacities may be similarly placed.

The side frame member 70 is provided with rein forced end portions 78formed with openings 80 to receive a brass bearing 81 that is shaped tocomplement the shape of the respective openings 80 and that rests on topof the housing 14 or axle as the case may be (see FIG. 2). The members70 also include a reinforcing hollow rib portion 82 under the springseat portion 24 and an upstanding sidewall structure 84 reinforced as at85 that is intended to resist lateral forces imposed by the bolster.Sidewall 84 preferably has applied thereto as by welding a hardenedwear-resistant surface plate 86 for cooperation with a similar platecarried by the bolster. The side frame member 70 rests on its hearing 81that in turn rests on the respective axle housings 14 or axle as thecase may be. As part of the assembly procedure, the side frames aresecured in place by applying suitable filler members 89 within therespective openings 80 and securing them in place with bolts 87.

In addition to compression springs 74, it is preferable that a snubberdevice be applied between the bolster and the respective side frames,where indicated at 90 in FIG. 2, and for this purpose, the side framespring seat area 24 is appropriately formed as at 92 to receive asuitable snubber 90 which preferably is of the type disclosed in my US.Pat. Nos. 2,130,678 and 2,210,840 (the disclosures of which are herebyincorporated herein by this reference).

In the embodiments illustrated, the side frame 12 comprises two castings70 joined together by crossmember plates 94 riveted in place as at 96.However, in an alternate arrangement, the side frames 12 are cast as asingle casting with a portion shaped comparably to member 94 integrallyconnecting the two members 70.

In either case, the side frame cross-member 94 is formed with acentrally disposed opening where indicated at 96 (see FIG. 9) to receivethe kingpin 32, which opening 96 is reinforced by a suitable flangedsleeve 98 affixed as by welding to the top of the member 94 and asuitable annular plate 100 affixed as by welding to the under surface ofmember 94.

The end portions 78 of the side frames define opposed upstandinglongitudinal thrust receiving surfaces 102 and 104 to which are affixedas by welding hardened wear-resisting plates 106 and 108 respectivelythat cooperate with corresponding plates affixed to the bolster.

The bolster 28 is illustrated in FIGS. 4-8, and generally comprises aone-piece casting defining relatively long side portions 110 and 112joined together with the centrally located annular guide structure 36 byreinforced arm structures 114. v

The undersides of the respective bolster side portions 110 and 112 areshaped to define the bolster spring seats 30 that correspond inconfiguration to the side frame spring seats 24 and are adapted toreceive the upper ends of compression springs 74. The bolster sideportions 112 and 110 are each formed with extensions 1 16 that cooperatewith the extension 76 of the respective side frames to seat therespective outwardly disposed row of springs 74.

The ends 118 and 120 on the respective bolster side portions are formedwith flat longitudinal thrust receiving surfaces 122 and 124,respectively, to which are applied as by welding the respective hardenedwear-resisting plates 126 and 124 that are intended to cooperate withthe respective side frame wear plates 108 and 106, respectively (seeFIGS. 1 and 2).

The bolster side portions 110 and 112 are each formed with flat lateralthrust resisting surfaces 130 and 132 to which are respectively appliedhardened wear-resisting plates 134 and 136 that cooperate with therespective plates 86 of the side frames (see FIG. 9).

Referring to FIG. 9, the proportioning of parts inthe bolster guidestructure 36 will bring either the bolster wear plates 128 intoengagement with the side frame wear plates 106, or the bolster wearplates 126 into engagement with the side frame wear plates 108,depending upon which end of the car is moving forward.

The side bearings 42 cooperate with the upper surfaces 140 of therespective bolster side portions 110 and 112 and each side bearinggenerally comprises an arcuate plate member l42 that is affixed to thebolster as by welding at 144 and is recessed as at 146 for applicationthereto of a strip or layer 148 of any suitable anti-friction materialsuch as bronze on which rests a steel block 150 that is received in arecess 152 formed in the car body bolster side bearing attachment 154,which recess 152 substantially complements the shape of a block 159 (seeFIGS. 5 and 6). Attachment 154 is affixed to the body bolster or itsequivalent in any suitable manner.

Applied over the plate 142 is a suitable cover 156 which is closelyreceived about the block 150 and rides on top of the plate 142 toprotect the wear surface 158 on which the block 150 rides under theswinging action that the trucks will have with respect to the car bodyas the car rounds curves and the like. It is preferable that lubricantfilled sponge be applied about the block 150 under cover 156 whereindicated at 160, and that the cover 156 include a suitable passagestructure where indicated at 162 for adding lubricant as may be requiredsee FIG. 6).

The arm structures 114 of the bolster may be sectioned in the generallychannel shaped configuration indicated in FIG. 8A, with the deeper sides167 on either side of the truck facing each other so as to insureadequate resistance to lateral thrusts imposed on guiding structure 36.

The relative length of the bolster side sections 110 and 112 lengthwiseof the car (which preferably has a dimension on the order of about 45inches) is a special significance since the proportioning involvedavoids any tendency of the bolster to rock or twist about its axistransversely of the truck, thus overcoming a serious problem experiencedwith conventional truck bolsters. The supporting action of the springgroups is also spread out adequately to insure minimum bending moments.In a specific embodiment of my invention, the dimension of sections 110and 112 lengthwise of the car is 45 inches, as compared to acorresponding dimension of about 17 inches for standard bolster designs.

The axles 16 of the embodiment of FIGS. l-14 are formed with hubportions 170 (see FIG. 10) at either end thereof on which is pressfitted a wheel hub 172 which in turn has press fitted on it therespective individual wheel discs 173 that each comprise wheel plate 62,flange 64, and rail engaging rim surface 174 (which is preferably of thestandard AAR cylindrical type). As already indicated, the parts involvedshould be proportioned so that the wheel has a bore 175 on the order of15 inches to reduce the radial dimension of wheel flange 64.

The axle housings 14 each comprise a tubular member 176 formed adjacenteither end thereof to define a seat 178 on which the respective sideframe mounting members 81 rest. As indicated in FIG. 10, the

axle housings 14 are formed so that the cylindrical surface 182 definingtheir respective bores is spaced from the axle 16.

Operatively interposed between each end portion 20 of each axle housing14 and the adjacent wheel 18 is the bearing unit 22 which is bestillustrated in FIGS. and 10A.

Bearing unit 22 in the form of FIGS. 1-14 is of the tapered rollerbearing type and comprises an inner race or hearing cone 190 pressfitted onto a reduced portion 192 of the respective tubular housingmember end portions 20, an outer race or bearing cup 194 press fittedinto a recess 196 formed in the wheel hub 172, and a plurality oftapered roller bearings 198 interposed between the races 190 and 194 incircumambient relation about the inner race 190 and held in spacedrelation by retainer device or cage 200.

The cage 200 is annular in configuration and preferably formed from asuitable antifriction metal such as bronze; it is broached or otherwisesuitably formed to define equally spaced openings 202 thereabout inwhich the respective rollers 198 are received.

It is to be noted that the inner and outer races and their rollerbearings of unit 22 are each of single row construction, and inaccordance with this invention, the comparable bearing unit at the otherend of the axle 16 is applied in opposed fashion so that the bearingunits 22 of each axle are in effect, self-balancing. As indicated inFIGS. 10 and 10A, the raceway surfaces 204 and 206 of the respectiveinner and outer races are frusto-conical in configuration and divergeinwardly of the truck (that is, in the direction of the longitudinalcenter line of the car). The unit 22 that is applied to the other end ofthe axle 16 is similarly oriented, and thus has its parts disposed in aposition that is the reverse of that shown in FIGS. 10 and 10A.

Associated with each unit 22 is a closure plate 208 that is receivedover the end portion 20 of the respective axle housings l4 and issecured in place by suitable bolts 210. Ring 212 encircling the endportion 20 of the respective housing 14 is employed to prevent theentrance of dirt into the bearing unit 22; it is of the conventionallocking ring type that is made of spring steel or the like and issnapped into the position shown.

Cover plate 208 in accordance with this invention is formed with a rib214 defining annular guiding surface 216 which is positioned andproportioned to be engaged by the end surface 218 of the roller bearingcage 200. Thus, as distinguished from conventional roller bearing units,in which movement of the rollers outwardly of the bearing is precludedby a steel-on-steel contact with a shoulder of the inner bearing cone,the rollers 198 are guided by the engagement of cage surface 218 withcover plate surface 216, which thus provides a guiding body ofanti-friction material between the inwardly disposed ends of the rollers198 and the cover plate 208.

It is preferred that the running clearance of rollers 198 between theinner and outer races be on the order of 0.005ths of an inch toaccommodate expansion during operation, and this clearance may becontrolled by applying appropriate shims between the cover plate andouter race where indicated at 220. When adjusted for this preferredrunning clearance, the axle housing moves freely endwise about fourhundredths of an inch.

The cage 200 at its outer end is flared as at 222 and is provided withcylindrical surface 224 adapted to engage the surface 226 of the outerrace to provide some guiding action on the outwardly directed end of thecage during operation of the truck, so as to insure that the cage runscentered with respect to the outer race 194.

The wheel hub 172 and the cover plate 208 define a chamber 228 in whichthe bearing unit 22 is mounted, which chamber is preferably charged withoil and provided with a suitable oil inlet that is closed by a suitableremovable plug, similar to that indicated at 310 and 312, respectively,in the form of FIGS. 16 and 17.

The roller bearing unit 22 has several important advantages. Forinstance, the desired looseness or running clearance of the rollers 198may be obtained with only one-tenth of the misalignment occasioned inconventional roller bearing units employed for outboard mounted sideframes, as roller units 22 are approximately 10 times as far apart asthe two sets of rollers in a typical AAR roller bearing unit for axlejournals.

Furthermore, the outer race 194 of the bearing unit 22 revolves with thewheel 18 and achieves much better oil distribution about the rollers198.

Moreover, more rollers pass through the load supporting zone of thebearing (the lower segment of the arc struck by the bearing unit 22),which will be based on the difference in diameters of the races and 194.

And, as already indicated, the movement of the rollers 198 is guidedthrough a guide member of anti-friction material, which materiallydecreases the rate of heat build-up in the rollers.

In the embodiment of FIG. 15, the axle housings 14 are omitted and theside frames 12 are applied directly to a reduced portion 240 of the axle16A in the manner indicated in FIG. 15, which otherwise is similar tothe side frame application shown in FIG. 10.

In the embodiment of FIG. 15, the end 44 of each axle 16A includes atapered portion 242 which receives a bearing member 244 formed frombronze, or the like, that is press fitted into the bore 246 of a wheelhub 248 on which the wheel disc 249 is press fitted in any suitablemanner.

The wheel hub 248 forms a housing for the bearing 244 and is formed todefine a plurality of annular lubricant reservoirs 250 interconnected bypassages 252, which may be supplied with oil through suitable passages254 and 255 closed by suitable removable plugs 256 and 258,respectively.

The bearing member 244 is formed with a plurality of spaced orifices 260that lead to its bearing surface 262, and that are staggered axially ofthe axle 16A to achieve uniform oil distribution along the surface 262.Preferably, the bearing 244 is formed with similar orifices 260 inalignment with each reservoir 256, although only one set of the orifices260 are shown for clarity.

Preferably, a lateral bearing 262A formed from bronze or the like isinterposed between the lock washer 50 and the wheel hub 248 and the endportion 264 of bearing 244 that is aligned therewith in the area of lockwasher 50.

Under normal operation, the wheels 18A carry vertical loads on the oilfilm that builds up between the bearing 244 and the axle portion 242.

In the specific embodiment illustrated in FIG. 15, the axle end 44defines a collar 266 between which and the inner end 268 of bearing 245is received an annular bearing member 270 that is likewise formed from asuitable antifriction material such as bronze, and against which bearingmember 244 is pressed by the application of nut 46 to the axial end 44.Nut 48 serves to lock nut 46 in place.

One of the important features of the embodiment of FIG. is that isprovides independently rotating wheels for the truck. This eliminatesthe tendency of standard AAR trucks having wheels with tapered treads toshift from side to side as the wheels which are made fast to therespective axles) try to follow the track rails. In this embodiment, thetruck wheels are free to freely follow the track rails in a mannersimilar to the wheels of a highway trailer following the highway.

While this embodiment of the invention is shown as embodying a frictionbearing arrangement, the same concept may be embodied employing asuitable roller bearing unit for journalling the wheel on the end of theaxle.

In the embodiment 10B of FIGS. 16 and 17, the tubular axle housings 14are retained and are provided with end portions 203 which cooperate withthe friction bearing unit 22B associated with wheel hub 280 on whichwheel disc 281 is press fitted.

Wheel hub 280 defines a hub portion 282 that is press fitted on the axleend 170. Hub 280 is formed to define annular portion 284 in which ispress fitted a cylindrical bearing member or sleeve 286 that is pressfitted into place and is provided with bearing surface 288 on whichrides a bearing shoe 290 that is keyed to a reduced portion 292 oftubular housing end portion 208, as by employing pin 294. Bearing member286 and shoe 290 may be formed from a suitable antifriction materialsuch as bronze and shoe 290 should be proportioned to extend acrossabout 130 degrees of arc at the lower sector of the housing end portionB. Annular cover plate 296 is secured in place by suitable bolts 298applied to hub 280 which serves to retain bearing member or sleeve 286in place, and the wheel hub 280 and axle housing 14 are proportioned toprovide the annular spaces indicated at 300, 302, 304, 306 and 308 thatare filled with lubricant through a suitable port 310 that is closed bysuitable removable plug 312. It is to be noted that the space 308extends across the axle to the other end thereof and connects with asimilar space 308 at the other end of the axle.

Bearing sleeve 286 is preferably formed with a plurality of openings 310thereabout in alignment with spaces 304 and 306 to provide ready accessof lubricant to load bearing parts of the bearing.

In the embodiment 10B, the tubular axle housings 14 must be restrainedagainst revolving which may be done by a lug welded to the side frameengaging a suitable notch in the axle housing or some other suitablemeans.

It will therefore be seen that I have provided a railroad car truck thatis especially adapted for application to freight cars of the lOO-ton andover capacity, yet which is smaller and lighter in weight thanconventional truck arrangement. One principal reason for this is thatthe loads applied to the truck are transmitted almost directly to thetrack rails in substantial vertical alignment therewith.

This substantially eliminates bending moments on the bolster axles andwheels.

As has been pointed out, the weight of the body is applied to thebolster directly over the spring groups that support the bolster, and inthe illustrated embodiment the side bearings provide for adequatepermanent lubrication thereof.

It is important that the snubber employed be of the type that acts onlyvertically when in its operating position on the truck as this avoidsthe application of restrictions on bolster movement that will result inbolster twisting on vertical movement, as sometimes happens inconnection with conventional friction type snubbers that act in opposedrelation on either side of the bolster.

In the embodiments of FIGS. l-l4, 16 and 17, the axle housings providean added safety factor in addition to protecting the axles and providinga mounting arrangement for the side frames. For instance, if a car thatincludes trucks 10 or 108 is in a wreck, it is quite likely that eitherthe axle 16 or the housing 14 will hold, thus keeping the truck wheelsaligned with the trackway and the car on the right of way.

Furthermore, in these embodiments of the invention, the wheel axles donot carry the car body weight as the car body weight is applied to thewheels through the axle housings and the bearing units interposedbetween such housings and the wheels.

In all embodiments of the invention, the center pivot structure at thekingpin provides only guiding action on the truck and no weight supportinsofar as holding up the car body is concerned. As indicated, the loadof a body is transferred through the truck in the area of the sidebearings, spring groups and side frame mountings that are disposed asclose as practical to vertical alignment with the rails. The significantdifference between applicants arrangement and those of the prior artwill be better appreciated upon considering that a 79-inch spread existsbetween the springs supporting the load in the standard AAR truck asagainst 43 inches in a dimensioned embodiment of the invention betweenthe midportions of the side frame end portion 78 as applied to eachaxle, which, as is indicated in FIGS. 3 and 13, are in substantialalignment with respective spring groups on either side of the truck.

The foregoing description and the drawings are given merely to explainand illustrate my invention and the invention is not to be limitedthereto, except insofar as the appended claims are so limited, sincethose skilled in the art who have my disclosure before them will be ableto make modifications and variations therein without departing from thescope of the invention.

What is claimed is:

1. In a tapered roller bearing unit of the type including a stationaryinner bearing cone, a rotatable outer bearing race, and a plurality oftapered rollers interposed between said cone and said race and mountedin a retaining cage to space said rollers about said cone, theimprovement wherein:

said cage comprises an annular member formed from an antifrictionmaterial and defining spaced openings thereabout in which said rollersare rotatably received free of means journaling same relative to saidcage,

said rollers having their larger ends disposed adjacent one end of thecage,

said one end of said cage being formed to define an annular guidesurface facing away from said larger ends of said rollers,

a cover plate fixedly mounted relative to said outer race,

said cover plate defining an angular guide surface positioned andproportioned to be engaged by said cage guide surface during operationof said unit for limiting movement of said cage in the direction of saidplate,

with the other end of the cage being formed with an annular surface formaintaining said cage in centered relation relative to the outer race,an annular guide means fixed with respect to said

1. In a tapered roller bearing unit of the type including a stationaryinner bearing cone, a rotatable outer bearing race, and a plurality oftapered rollers interposed between said cone and said race and mountedin a retaining cage to space said rollers about said cone, theimprovement wherein: said cage comprises an annular member formed froman antifriction material and defining spaced openings thereabout inwhich said rollers are rotatably received free of means journaling samerelative to said cage, said rollers having their larger ends disposedadjacent one end of the cage, said one end of said cage being formed todefine an annular guide surface facing away from said larger ends ofsaid rollers, a cover plate fixedly mounted relative to said outer race,said cover plate defining an angular guide surface positioned andproportioned to be engaged by said cage guide surface during operationof said unit for limiting movement of said cage in the direction of saidplate, with the other end of the cage being formed with an annularsurface for maintaining said cage in centered relation relative to theouter race, an annular guide means fixed wiTh respect to said outer racefor engaging said cage other end surface.
 2. The improvement set forthin claim 1 wherein: said cage is of generally frusto-conicalconfiguration and has said other end thereof flared outwardly thereof todefine said cage other end surface.
 3. The improvement set forth inclaim 2 wherein: said outer race is formed with an annular surface toform said guide means, said outer race and said cage other end engagingsurfaces being substantially cylindrical in configuration.